The present invention relates to weight and balance or moment calculators and, more particularly, to calculators used with small aircraft to determine whether the load the aircraft is carrying is properly disposed for a safe flight.
The necessity of properly distributing loads is particularly important for small aircraft such as are used in short commuter flights or for specific charter purposes where the passenger capacity ranges from as few as 4 to up to 12 seats. Additionally, as is well known, fuel consumption can alter the weight-moment balance of some types of small aircraft and this must be compensated for in order to insure a safe flight particularly where wind conditions are adverse.
As a consequence of the necessity of properly distributing the loads in a small aircraft, a variety of different types of calculators have been proposed for use by pilots in order to facilitate the disposition of loads in such aircraft. One particular type of calculator is of the kind which makes advantageous use of graphs provided by the aircraft manufacturer which displays what is termed the "moment envelope" which displays a tolerance characteristic of a specific type of aircraft. Such prior art devices, as well as others, do not readily lend themselves to use where frequent changes in the load dispositions in an aircraft occur such as on small commuter planes or short cargo hauls. Specifically, a number of the known calculators require the pilot to completely recalculate the weight-balance tolerance should any large alteration in the load occur such as the discharge of one or more passengers or, in some cases, even the filling or emptying of one of the fuel tanks or bags.
As is well known, small aircraft operators, of necessity, must operate on tight schedules in order to remain competitive and, accordingly, the need for a device that can rapidly and accurately calculate weight-moment tolerances is evident in order to minimize interference with flight schedules and assure a safe load disposition for the flight.
Accordingly, it is an object of the present invention to provide a weight balance calculator that will eliminate the necessity for any arithmetical calculations as well as one which will efficiently utilize the moment envelope graph provided by the aircraft manufacturer so as to enable the pilot to rapidly determine any variations in the weight moment tolerance due to loading or unloading during a flight stopover. Additionally, the calculator of the present invention will enable the pilot to determine precisely the extent to which a load should be shifted in order to bring the weight-moment balance within the tolerance of the aircraft.
In a preferred embodiment, the present invention utilizes a modification of the standard flight computer or calculator which is conventionally employed to resolve wind vector flight plottings. The standard flight calculator consists of an outer support member carrying a range of indicia markings in angular degrees and an inner movable dial or disc member which is circular and is divided into 360.degree. increments corrsponding to flight or wind directions. According to the present invention, the central portion of the inner disc is provided with a transparent section. In this section there are formed a plurality of parallel slots with a central slot extending across a diameter of the section. Additionally, a slotted channel is provided on the underside of the calculator to receive and support a card carrying a moment envelope graph characteristic of a particular aircraft.
As will be explained in more detail hereinafter, with the foregoing device, knowing the magnitude of the weights being placed in an aircraft, a pilot will be able to rapidly plot in an accurate manner the sum of the vectors representing the moment arms of the loads to be carried by the aircraft. Moreover, the changes in the loads can be immediately determined by simple visual inspection of the plotted graph relative to the moment envelope which will indicate to the pilot whether any rearrangement of the load is necessitated by any additions or subtractions to the aircraft cargo.
The calculator of the present invention will permit more rapid and accurate calculations of weight-moment tolerances than has previously been possible and will eliminate the necessity of carrying out intricate mathematical computations in order to arrive at a safe tolerance determination. Further advantages will become apparent as consideration is given to the following detailed description and accompanying drawings, in which: